1. Field of the Invention
The present invention relates to an apparatus for connecting strips in which a rear end of a preceding strip is connected to a front end of a succeeding strip by butt welding.
2. Description of The Prior Art
A conventional apparatus for connecting strips is disclosed in Japanese Patent Laid-Open No. 171590 (1982) is shown in FIGS. 1 to 4 herein in which
FIG. 1 is a front view showing that apparatus;
FIG. 2 is a plan view showing the apparatus of FIG. 1;
FIG. 3 is a side view showing a sectioned state of the apparatus of FIG. 2; and
FIG. 4 is a side view showing a welded state of strips.
Referring now to FIG. 1, strips travel horizontally in a direction of from a front side to a back side as seen on the drawing through a transfer frame 2 which will be mentioned later. In addition, referring to FIG. 2, a travelling direction is seen in the up and down direction as seen on the drawing. Referring to FIGS. 3, 4, strips 6a, 6b travel in a direction shown by A in the drawing.
Referring again to FIG. 1, reference numeral 1 designates a base table having a width sufficiently longer than that of the strip and reference numeral 2 designates a transfer frame movable in a direction of a width of the base table 1 or the strip, and said transfer frame 2 being provided with a cutting device 25 and a welding device 16, which will be mentioned later, which are placed thereon. The base table 1 is provided with a groove 1a formed in a direction of width at a central portion in a travelling direction of the strip, the groove 1a being provided with a hydraulic cylinder 3 for moving the transfer frame 2 in a direction parallel thereto at a lower portion thereof, with a tube being fixed to the transfer frame 2 a rod of the cylinder 3 being fixed to the base table 1, the groove 1a is provided with a guide 4 mounted on a side thereof in a direction of width of the base table 1. A lower member of the transfer frame 2 is provided with a groove 2a formed on a bottom surface thereof extending all over the length thereof and a sliding face engaging the guide formed on a front face and a rear face thereof so that the lower member of the transfer frame 2 may be inserted into the groove 1a with the hydraulic cylinder 3 positioned within the groove 2a. Only that portion of the base table 1 in the vicinity of the groove 1a is shown in FIG. 1. Upon operating the hydraulic cylinder 3, the transfer frame 2 is transferred in the direction of width of the base table 1.
Referring again to FIG. 3, 6a, 6b designates a preceding strip and a succeeding strip, respectively, of a base table face 1b at a downstream side of the apparatus and a base table face 1c at an upstream side thereof. The groove 1a is located between the faces 1b, 1c and extends below the faces. The base table face 1b is provided with an outlet side clamping device 5 for clamping the preceding strip 6a. In addition, a tube of a hydraulic cylinder 9 is fixedly mounted on the base table face 1c. A rod of the hydraulic cylinder 9 is connected to a clamp-installing table 42 placed on the base table face 1c, said clamp-installing table 42 being provided with an inlet side clamping device 8 for clamping the succeeding strip 6b, installed in an opposite relation to the outlet side clamping device 5 with the groove 1a positioned between them. The outlet side clamping device 5 and the inlet side clamping device 8 comprise a hydraulic cylinder 7 and a hydraulic cylinder 10, respectively, as a driving source thereof and they are fixedly mounted on an upper fixing device (not shown). The clamping device 5, 8 clamps and releases the strip 6a, 6b by the action of the hydraulic cylinder 7, 10, respectively. In addition, the inlet side clamping device 8 can be transferred in the strip-travelling direction by the action of the hydraulic cylinder 9.
An upper member of the transfer frame 2 is provided with a hydraulic cylinder 21 fixedly mounted thereon with a tube on an upper side and a rod on a lower side, the rod being provided with a movable cutting edge device 20a mounted thereon. The hydraulic cylinder 21 is provided with guide rods 22a, 22b connected to the movable cutting edge device 20a standing on both sides in the direction of width of the base table 1, the guide rods 22a, 22b being engaged with guide rings provided on the upper member of the transfer frame 2 so as to vertically guide the transfer frame 2 up and down. The movable cutting edge device 20a is provided with two pieces of cutting edge with a suitable interval in the strip-travelling direction. The transfer frame 2 is provided with a hydraulic cylinder 23 fixedly mounted thereon with a tube on a lower side at a position opposite to the cylinder 21 of the lower member of the transfer frame 2 and connected to a fixed cutting edge device 20b with a rod on an upper side, the hydraulic cylinder 23 being provided with guide rods 24a, 24b standing on said fixed cutting edge device 20b on both sides in the direction of width of the base table 1, and the guide rods 24a, 24b being put in guide cylinders provided on the lower member of the transfer frame 2 side by side so as to vertically go up and down. The fixed cutting edge device 20b is provided with two pieces of cutting edge with a suitable interval in the strip-travelling direction. A cutting device 25 is composed of the movable cutting edge device 20a, the fixed cutting edge device 20b, the hydraulic cylinders 21, 23 and the guide members 22a, 22b, 24a, 24b. The fixed cutting edge device 20b is raised by the action of the hydraulic cylinder 23 until it is brought into contact with the strip and then the movable cutting edge device 20a is lowered by the action of the hydraulic cylinder 21 to cut the strip at two positions of the rear end of the preceding strip 6a and the front end of the succeeding strip 6b. The cutting device 25 can be transferred to the position, where the clamping device is installed, with the movement of the transfer frame 2.
The upper member of the transfer frame 2 is provided with a rectangular rail-holding plate 40 hanging down therefrom with a plate face thereof in the strip-travelling direction with a suitable distance in the direction of width from the portion where the hydraulic cylinder 21 is installed, the rail-holding plate 40 being provided with a rail 13 arranged horizontally in the direction of width of the strip, and the rail 13 being provided with a carriage 12 carrying a movable processing head 11 hanging down therefrom for emanating laser beams. The carriage 12 is provided with a motor 14 for driving the carriage 12 placed thereon. Laser beams emanated from a light source 41 enter the processing head 11 through a transmission system 15, where an optical path and an energy-density of the laser beams are changed by means of an optical system, and then are emanated downward from the processing head 11. The lower member of the transfer frame 2 is provided with a hydraulic cylinder 18 mounted thereon with a rod turned upward at a position below the rail-holding plate 40, the hydraulic cylinder 18 being provided with a welding back bar 17 connected thereto. The hydraulic cylinder 18 is provided with guide rods 19a, 19b hanging down from the welding back bar 17 on both sides in the direction of width of the base table 1, said guide rods 19a, 19b being put in guide cylinders installed on the lower member of the transfer frame 2 side by side so as to be capable of vertical up and down movement. The welding back bar 17 can be moved in an up and down direction by the action of the hydraulic cylinder 18. A welding device 16 is composed of the processing head 11, the carriage 12, the rail 13, the rail-holding plate 40, the motor 14, the welding back bar 17, the hydraulic cylinder 18 and the guide members 19a, 19b and can be transferred to a position, where the clamping device is installed, with the movement of the transfer frame 2.
In operation, when the rear end of the preceding strip 6a travelling in the direction of an arrow A in FIG. 3 arrives at an appointed position relative to the outlet side clamping device 5, the hydraulic cylinder 7 operates, thereby clamping the preceding strip 6a by means of the outlet side clamping device 5. Also the succeeding strip 6b travels in the same direction as the preceding strip 6a. Upon forming an appointed space between the rear end of the preceding strip 6a and the front end of the succeeding strip 6b, the hydraulic cylinder 10 operates, thereby clamping the succeeding strip 6b by means of the inlet side clamping device 8.
After both the strips 6a, 6b are clamped by means of both the clamping devices 5, 8, the transfer frame 2 is transferred by the operation of the hydraulic cylinder 3, thereby arranging the respective cutting edge devices, 20a, 20b between both the clamping devices 5, 8, as shown in FIG. 3. Under this condition, the fixed cutting edge device 20b is raised by the operation of the hydraulic cylinder 23 so as to be brought into contact with both the strips 6a, 6b. Subsequently, the movable cutting edge device 20a is lowered by the operation of the hydraulic cylinder 21 to cut the rear end of the preceding strip 6a and the front end of the succeeding strip 6b at the same time. Upon completion of the operation of the cutting device 25, the transfer frame 2 is transferred again by the operation of the hydraulic cylinder 3 to arrange the welding device 16 between both the clamping devices 5, 8, as shown in FIG. 4. The succeeding strip 6b is advanced by the operation of the hydraulic cylinder 9 under the condition that it is clamped by means of the inlet side clamping device 8 to bring the rear end of the preceding strip 6a into contact with the front end of the succeeding strip 6b. Upon completion of the operation of the inlet side clamping device 8, the welding back bar 17 is raised by the operation of the cylinder 18 so as to arrive at a position of contact with both the strips 6a, 6b. Subsequently, the carriage 12 is transferred by means of the motor 14 so that the processing head 11 may be located above the position, where both the strips 6a , 6b are brought into contact with each other, and laser beams are incident upon that position from the processing head 11 to weld both the strips 6a, 6b.
The area of the strips which is connected after being welded is dependent upon the shapes of contacting portions of both the strips. In general, a problem has occurred in that the contacting portions of plates cut by means of a cutting device provided with a fixed cutting edge and a movable cutting edge form a very small gap (B in FIG. 5) in the direction of thickness resulting from die wears, burrs and the like, as shown in FIG. 5, and it is difficult to secure the straightness of the end face, so that it is difficult to improve the connected portion in welding quality.